Process for coating molds for metal ingots.



PROCESS FOR COATING MOLDS FOR METAL INGOTS. t APPLlcAnofHLED Dic. 16. |915. Lw.. Patented oct. 23,1917.

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G. F. DOWNS. Pnoczss ron comme Moms fon mam mams.

APPLICATION FILED DEC. I6. 1916- v 19243;?17, `Patented. Oct. 23.1917.

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'GEORGE FRANCIS DOWNS,

0F BUFFALO, 'NEW YORK.

PROCESS FOR COATING IVIOLDS FOR METAL INGOTS.

Specification of Letters Patent.

Patented Oct. 23, 191. 7.

Application filed December 16, 1916. Serial No. 137,417.

To all whom t may concern:

Be it known that I, GEORGE F. DOWNS, a citizen of the United States, and a resident of Buffalo, in the county of Erie and State of New York, have invented certain new hand useful Improvements in Processes for Coating Molds for Metal Ingots; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to theletters of reference marked thereon, Which form a part of this specification.

This invention relates toi an improved process for coating the inside surface of steel-ingot-casting molds, and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

A factor of primary importance in steel l making is the preparation of the steel ingot inself, and particularly as to the formationand condition of its outer surface. After the molten metal has been poured into thev result in seams and surface defects that are produced when rolling the ingot.

It has been customary heretofore to coat the inner surface of the mold to insulate the inner mold surface and to prevent adhesion of the ingotfto said surface during the cooling process. To this end, various washes, consisting of mixtures of water with clay, ganister, lime, or graphite, in certain proportions to give the proper fluid consistency, have been used. These washes have been applied in various ways, as for example, by spraying, by means of brushes or swabs, and by splashi.ng,-tl1e end and aim in each case, being to cover as much of the inside surface of the mold as possible. None of the above methods. however, have been capable of depositing the insulating. non-adherent wash in a uniform layer or film upon the inside surface of the mold.

The object of my improved process and apparatus is to apply an insulating Wash of the' kind described, in a uniform, even, smooth layer or film, completely covering the entire inner surface of the mold, and filling in and smoothing over all inequalities and depressions therein.

In carrying out my process, I provide a wash consisting of water and of clay, ganister, lime, or graphite, in the necessary proportions to produce a mixtureof such fluid consistency that it will stick or adhere to the surface of the mold when applied thereto. This mixture is' placed in a tank or other suitable reservoir, and the mold is partly or Wholly dipped into,'or submerged in the fluid mixture, so as to bring all of the inner surface of the mold into contact with the mixture or wash.

The mold is then withdrawn from the Huid mixture and the outside surface of the -mold is washed or cleaned by sprays of water. or otherwise, to remove the insulating wash or mixture from the outer surface of the mold. The mold is then in readiness for use in pouring the molten metal to form the ingot.

The accompanying drawings illustrate my improved apparatus and will more clearly and fully demonstrate my improved process.

In the drawings:

Figure 1 is a diagrammatic View, representing in vertical elevation and partially in vertical section, an apparatus for carrying out the'process.

Fig. 2 is a view showing the dipping tank in vertical section, in a plane at right angles to that of Fig. l, with the mold car placed adjacent thereto.

Fig. 3 is a top plan view of the dipping tank.

Referring now to that embodiment of my improved apparatus'A for carrying out my process 10-10 indicate the upright beams of a traveling crane structure; 1l-11, the upright posts; 12-12. I-beam stringere., and- 13-l3, the rails -supported thereon, and providing tracks for the wheels 111--1-1 of a traveling crane 15. The upright beams 10-1() are connected together at the top by suitable tie members 16, andthe Lbeams 12 are braced from said upright members by means of plates 17`17; 18 indicates a transverse shaft mounted on the traveling crane 15 and adapted. through suitable gearing 19-19 to drive the wheels 14-14 along the tracks 13-13; 2O indicates the motor for driving the shaft, and 21, the operators cab in which is providedI suitable mechanism for controlling the motor. 22 indicates a trans- Versely moving carriage mounted on rails 23 on the top of the traveling crane 15; a differential drum 24 is mounted on this carriage, and is driven by gearing 25, actuated in a familiar manner by a motor 26 mounted on the carriage, and arranged for control by the operator in the cab'21.

27 indicates an open vessel or tank set in the ground or floor 28, upon which the traveling crane structure is erected. This tank consists, as shown, of a substantially rectangular box made of concrete or other suitable material, and preferably provided with a metallic sheet lining 29. r1`his tank, as shown, projects above the floor or ground level 28. A trackway 30 is arranged alongside the tank 27 for a mold car 31. A4'llhe tank 27 constitutes the dipping tank and contains the mixture of insulating wash or fluid, consisting of water and of one of the several substances, clay, ganister, lime or graphite, as heretofore described.

The dip ing tank is provided. with means for agitating the fluid mixture contained therein. As shown, this means consists of an air blast pipe 32 which is located at one side of the tank and which depends into the tank to a point near the bottom thereof. There is also provided means for heating the dipping mixture, which, as shown, consists of a steam pipe 33 leading from any convenient source of steam supply (not shown) and depending int-o the tank,

About the top of the dipping tank, there is placed a perforated pipe 34 built in the forml of a hollow rectangle, with the perforations directed toward the interior of the tank, and connected to a supply pipe 35. Said pipe has a hand valve 36 adaptedv to admit water under pressure into the pipe 34, from which it will be discharged through the perforations therein into the space defined by the four upright walls of the tank.

In the bottom of the tank is placed a basket 37 which is preferably4 in the form of a shallow, rectangular, open box having a perforated bottom wall 3S. This basket is provided with chains 39 connected to its four cornersthere being one chain at each end of the basket. Said chains are normally looped upon hooks 40 fixed in the end walls of the tank 27 near its top. These chains may be engaged by the grapple of the traveling crane 15 to withdraw the basket from the tank, as will be presently described.

45 indicates the ingot molds. Said. molds (one or more at a time,-two, as shown) are dipped in the fluid mixture in the tank by means of a grapple 46 attached to the blocks 47 connected in the usual mann-er by means of'ropes or chains 48, to the differential drum 24 of the traveling crane. The grapple is operated by the usual trip rope 49lin such a manner as to connect with or to be detached from the usual ears 45a on the molds 45.

1n carrying out the improved process by means of the novel apparatus hereinbefore described, the dipping tank is filled with one of the Huid insulating mixtures heretofore described. Steam is admitted through the pipe 33 in order to heat the mixture to a point somewhat below that of boiling water. At the same time, in order to maintain a thorough mixture of the wash, in which the solid material is merely suspended and not dissolved, air under pressure is admitted through the air pipe, and this air, escaping under the surface of the fluid in the tank, will agitate the mixture, maintain the solid material in suspension and produce and maintain a constant, uniform mixture.

A number of molds 45 are brought on the mold car 31 into a posit-ion adjacent to the tank 27. The traveling crane and the carriage 22 thereon, are brought in a familiar manner above the molds on the mold car, Aand the block and grapple 4?46, are operated to lift the molds from the mold car and to lower them into the tank 27 until they are completely immersed in the insulating fluid mixture therein. The molds are allowed to remain therein until a lm or coating of the insulating mixture has adhered to the surface of the molds. The differential drum of the crane is then operated to raise the mold from the dipping tank. As it is raised, the valve 36 is opened to supply water through the pipe 34, and this water is discharged through the perforations 0f said pipe against the mold, so as to clean and remove the wash or Vinsulating mixture from its outer surface. r1`he mixture, after it 4is Washed off the outer surface of the mold, drips back into the tank together with the wash water. The dipped molds are then returned to the mold car, and another mold4 or set of molds is brought above the tank and dipped into it, the process being continued as before. After all the molds have been treated in this way by the dipping process, they are taken away and the molten steel is poured into them in the usual manner.

The fluid mixture in the dipping tank is kept at a temperature between O and 200CJ F. rPhe advantage of maintaining the fluid mixture at this temperature, is that cold molds will be warmed up and raised to a temperature above that of the atmosphere during the dipping process, so that they will be in a more desirable 'condition as to temperature to receive the molten steel poured into th-em. Again, by maintaining the temioo Laia-,717.

perature'of the dipping mixture at the` degree described, the chilling ofhot molds, when dipped into the mixture, is prevented.

The spray water pipe flnot only acts to clean the outside surface 4of the vmold and i remove the insulating mixturel therefrom, but it'also, being cold andl drippinginto the'A dipping'tankfkeeps down the temperature of the dipping mixture below the boiling point of water, when the temperature of the mold that is being treated exceedsthat temperature. The addition of. water, in this washing process,

evaporation that takes place, due to the temperature of the dipping mixture.

By the dipping process herein described, the interior surface of the mold is provided .with a smooth, uniform layerof insulating to the surface of the mold, but drop back:-

into the molten mass.

Any sediment or particles of foreign sub.;

' stance that fall into the dipping tank, will collect in the basket 37, which may be withdrawn at intervals to remove the same.

In describing the process, I have illustrated apparatus by which the mold' is completely submerged in the fluid mixture contained in the dipping ".tank. It will be understood, of course, that complete submersion is not necessary, it being simply required to immerse the mold to such an extent that the fluid, insulating mixture will be brought into contact with the entire .interior surface of the mold, or with so much of said surface as will be brought into contact with the molten metal, whenv the ingot is poured.

I claim as my invention: i 1. The process of applying a uniform layer of insulating material upon the inner surface of an ingot mold havino' a vertically elongated ingot chamber, whic consists in dipping the mold into a fluid mixture of the insulating material so as to completely immerse the interior surface of the mold therein, and in then removing the coating of insulating material collected on the outer surface of the mold during the dipping process. r

2. The process of applying a uniform layer of insulating material upon the inner surface of aningot mold having a'vertically elongated, tubular ingot chamber, which to the fluidinixture in the dipping tank, -is compensated for by theAv .disposed ingot IAchamber, Whic l dipping the mold when-in `ajsubstantiallysulatingl substantially erect position into' a fluid mix-` consists in dipping -the..-mold V,When-int` a. i

ture of insulating. materials).` as. to com. pletely immerse the interiorlsurface-of .the

mold therein, said mixture being' maintainedY at a temperature ofv 1009, .F.- oi: more.. 3., The process ofA .applying layer olf-insulating material ,upon the inner; i

surface of ali-ingot. mold 'having a vertically. disposed' ingot chamber, which -consists in dipping the mold"`whenin asubstantially.-

the mold iswithdrawn from said mixture.

4. The process of applying :a -uniform layer of insulating material upon the inner surface of an ingot mold havinlga vertically n' consists in erectposition in a fluid-.mixture'of the in- .sfilating material, which is maintained at a temperature of 'from 1009 to.' l20,0"v F., the mold being dipped into-the`iuid mixture 'of the insulating material so as to completely limmerse its interior surface, and in washing the insulating materialcollected on the vouter surface-'of the mold from said outer surface, as the inoldis withdrawn from the u mixture.

5. The process 'of .applying ya'v .j 10o.

layer of insulating material upon the inner 'surface of4 an ingot `'mold having a ,verti-y callv disposedingot'chamber, which consists f in dipping the mold when'in a substantially erect position into a fluid mixture of the inmaterial so as to completely im-v merse t einterior surface of the mold therein, 'in agitating the'fluid mixture duringthedipping process, 4in heatin the mixture to a temperature substantia ly between and 2009 F., and in washing therefrom the insulating material collected on the outer` surface of the-mo/ld in the dippin process, as the moldis withdrawn from sai 6. The process of applying a uniform layer of insulating material upon the inner' surface of an ingot mold having a vertically disposed ingot chamber, which consists in dipping the lmold when in a substantially erect position into a fluid mixture of the insulating material, in agitating said mix ture during the dipping process, in heating 'said mixture to a temperature between 100 surface of an ingot mold having a vertically clisposed' in'go chamber', whichl consists in immersing the mold lwhen in a substantially erectposition in a tank containing a fluid mixture of insulating materia-l so as to' completely cover the interior surface of saidy mold, in agtating the mixture in said tank, in' heating saiol` mixture to a* temperature between 100o and 200D F., and in Washing the' outer surface of said mold as it is with drawn from' said tank, with cold water, andallowing said Water, together with the' insulting material Washed from. the outer suxillfgace of the mold to drop back into said ta In testimony that l claim the foregoing 15 

